I found foamcore pretty cheap at the art store, if you are in university or close by to one go to their art store and it will most likely be even cheaper. The link below gives you tips for using it.http://www.me.mit.edu/Lectures/SketchModelling/2.3-examples-foamcore-Image132.html
My last few apartments have been done on a pretty tight budget and I love color too. My living room (everyones fav place to sleep and chill when they visit us) is a really nice leaf green with a zen retro theme. Greens (or shades of) make just about any color you accessorize with look cool. Word to the wise if you go too dark or too bright with colors it can be really hard on the eyes! I've helped my sister re-do her room (in orange and leopard!). Also, when I did my co-op I got to "create" a room for a character in a small movie (baby blue with fuchsia and disco ball!). Here's my unsolicited suggestions / advice on room decorating!
I have issues with paying tonnes of cash for frames or any pieces at Urban Outfitters that I can do myself and get triple what I could there. I've made hung "portraits" of fabric swatches and t-shirts I like. Made matching/co-ordinating rugs and pillows out of second hand fabrics, same with the curtains. As long as you have a similar theme through out the room it'll look nice! For all the rooms, events and shows I've done I haven't spent more than $100 on the decorating (excluding furnature) and usually have enough left over for a nice bottle of well deserved wine!
You need a small can of paint (maybe try the pink and orange on the fab bedspread you bought).
Go to a garage sale or second hand store and get frames that you like the shape of.
At a fabric store or Walmart buy a 1/2 meter (or whatever size depending on your budget) of the animal prints you mentioned or whatever fabric you are using for your curtains.
With the above supplies you can make stuff like the over priced ones below! Good luck with the decorating, I hope I made sense!